The invention relates to a device for performing at least one medical function on a user. Furthermore, the invention relates to a method for disposing of components of an actuation and evaluation part of a device according to the invention, more particularly a disposable of the actuation and evaluation part. Devices according to the invention for performing at least one medical function are used, in particular, in the field of medical diagnostics or therapeutics. Thus, the device can for example be embodied as a sensor device for registering at least one bodily function of the user. By way of example, the device can be embodied as a sensor device for qualitative and/or quantitative detection of at least one analyte in a bodily fluid of the user. However, alternatively, or in addition thereto, the device can also be embodied as, for example, a medication device for administering at least one medicament to the user. A particular emphasis in the application of the present invention lies in continuous or discontinuous long-term monitoring of at least one analyte concentration in at least one bodily fluid such as, for example, interstitial fluid or blood. By way of example, glucose, cholesterol, lactate, general metabolites or other types of analytes or analyte combinations can be considered as analytes to be monitored. In principle, the present invention can also be applied to other medical fields, for example to diagnostics, therapeutics or surgery.
The prior art has disclosed a number of medical devices with diagnostic, therapeutic or surgical functions. In particular, monitoring and/or influencing certain bodily functions, more particularly monitoring one or more concentrations of specific analytes, plays a substantial role in the prevention and treatment of various diseases. Without restricting further possible applications, the invention is substantially described below with reference to blood-glucose monitoring, in particular with reference to continuous long-term blood-glucose monitoring over a number of hours, days, weeks or even months. However, in principle the invention can also be applied to other types of analyte monitoring and/or the monitoring of different types of bodily functions and to other fields in medicine. In particular, the invention can also be applied to medical therapeutics, for example to medication pumps such as insulin pumps.
Continuous measurements are also becoming ever more established in addition to so-called point measurements of one or more analytes, in which a sample of a bodily fluid is taken from a user in a targeted fashion. Thus, for example, a continuous glucose measurement in the interstitium (also referred to as continuous monitoring [CM]) has been established in the recent past as an important method for managing, monitoring and controlling a diabetes state, for example. Initially, this continuous monitoring is generally restricted to type I diabetics, i.e. diabetics who usually also wear an insulin pump. By now, use is generally made of directly implanted electrochemical sensors, which are often also referred to as needle-type sensors (NTS). Here, the active sensor region is brought directly to the measurement location, which is generally arranged in the interstitial tissue and converts glucose into electric charges, for example by using an enzyme (e.g. glucose oxidase, GOD), which charges are proportional to the glucose concentration and can be used as a measurement variable. Examples of such transcutaneous measurement systems are described in U.S. Pat. No. 6,360,888 B1 or in US 2008/0242962 A1.
Hence, current continuous monitoring systems are usually transcutaneous systems. In general, this means that the actual sensor is arranged below the skin of the user. However, an evaluation and control part of the system, which is also referred to as a patch, is generally situated outside of the body of the user, i.e. outside of the human or animal body. In the process, the sensor is generally applied by means of insertion instruments and inserted into the body tissue, which is likewise described in U.S. Pat. No. 6,360,888 B1 in an exemplary fashion. Other types of insertion instruments have also been disclosed. In general, a sensor is worn for a period of approximately one week; however, longer periods of wear, for example up to one or more months, are also possible. Thereafter, the sensitivity of the sensor generally drops off as a result of influences such as, for example, enzymes being used up and/or the sensor becoming encapsulated in the body, and hence the sensor can be expected to fail. Increasing the length of the period of wear is an area of active research. However, this means that the sensor, and optionally components such as an insertion needle directly connected thereto, should be embodied as replaceable elements. Accordingly, the sensor and, in general, further replaceable components of the device constitute a so-called disposable. However, the evaluation and control part of the system, or important, expensive parts thereof (such as e.g. high-resistance amplifier input stages and similar active elements), are generally reused, and so the device often comprises at least one reusable.
In the case of implantable sensors, the disposable generally comprises a so-called body mount, which can be affixed to the skin surface of the user, for example by means of a plaster, and by means of which the sensor that is inserted into the body tissue can be connected or is connected. The reusable, which contains the essential parts of actuation and/or evaluation electronics for measuring the analyte concentration, is then connected to this body mount. However, components can be arranged in the body mount itself. Thus, for example, at least one battery can be arranged in the body mount, and so when a body mount is replaced, and a new body mount and the reusable are assembled, the device is at the same time also equipped with a new source of energy.
The effect of this separation between disposable and reusable is that the user is not forced to replace or recharge the batteries while the sensor is used because the batteries must be replaced in any case when the body mount with the integrated battery compartment is replaced. However, according to relatively recent environmental guidelines, the batteries have to be able to be disposed of separately by the customer in the case of electrical devices that are powered by batteries. Hence, there is a challenge in developing a device that can be worn on the body of the user for a number of days in particular and hence is shielded from all acting environmental influences (damp, temperature variations, mechanical influence), wherein, however, it should at the same time be ensured that users can dispose of the batteries themselves after the period of wear.
The prior art has disclosed fundamentally different casings for medical devices, which either have completely welded-in batteries or have battery compartments that can be opened and closed a number of times. By way of example, US 2009/0253960 A1 describes an antenna unit with an antenna for receiving in-vivo information relating to a user. In the process, use is made of a cast-in antenna. In the process, flexible batteries are proposed inter alia, wherein the advantages of the flexible deformation of the cast-in battery on the body of the user are highlighted. However, separate disposal of the battery after the service life of the medical system is not possible or only possible with great difficulties.
Furthermore, the prior art has disclosed systems in which the battery can be replaced. By way of example, U.S. Pat. No. 6,498,951, U.S. Pat. No. 6,749,587 and U.S. Pat. No. 6,175,752 B1 illustrate various systems in which batteries can be replaced. To this end, U.S. Pat. No. 6,749,587 describes a battery compartment with a lid. U.S. Pat. No. 6,498,951 and U.S. Pat. No. 6,175,752 describe casings with two components, which can be detachably interconnected and in which provision is made for a hermetic seal of the battery compartment.
However, both known approaches have disadvantages because the above-described technical challenges are not overcome completely. Thus, in the one case, the battery cannot be disposed of separately and, in the other case, the replaceable embodiment of the battery and the technical requirements connected thereto, which relate to the battery compartment, represent significant technical challenges. In particular, in the case of battery compartments that should be opened reversibly, moisture-tightness must still be ensured because very high requirements are to be set in this respect, particularly in the case of medical devices that can be worn on the body of a user.